Pressure Vs. Power Factor

[CSEMARTIN]

I am loading 230 FMJ Zero's with 4.3 grains of N310. OAL is 1.255" with barely any crimp. I use Federal #150 primers. Power factor is 168,000.

My concern is that, even though my cases are not bulged, the primers are completely flat- more so than I've ever noticed with any other load. I'm concerned about it.

Is it possible to have a load that has too much pressure, but still just make power factor?

[RogerT]

Hi.

Whizz puts 4.6 gn behind the 230 FMJ RN he uses, OAL 32 mm, RWS LP primers and gets 180 PF loads.

But, he shoots a 625 revo, so his loads may not suit your gun. I have seen and shot his loads with no signs of exessive recoil or flattened primers.

[dajarrel]

I am loading 230 FMJ Zero's with 4.3 grains of N310.  OAL is 1.255" with barely any crimp.  I use Federal #150 primers.  Power factor is 168,000. 

My concern is that, even though my cases are not bulged, the primers are completely flat- more so than I've ever noticed with any other load.  I'm concerned about it. 

Is it possible to have a load that has too much pressure, but still just make power factor?

<{POST_SNAPBACK}>

I can't speak to whether you have a pressure problem or not, but I do know that I have always seen my loads with federal primers, especially in my 610 and 625 revolvers flatten the primer. I believe this is a result of softer metal in the primer itself rather than overpressure loads.

This has been my experience and yours may be different.

FWIW

dj

Edited October 17, 2005 by dajarrel

[CSEMARTIN]

dajarrel,

I've wondered the same thing, but what I'm seeing seems excessive.

[TDean]

I thought 310 was faster than clays? I only use 4.0gr clays for 230gr 45acp @168pf. What does the Vit load data recommend for 230gr and 310?

[Squishy]

V V n310 is not listed inVihtaVuori loading manuals. They say it is to fast a powder to put in large pistol cases. (To easy to double charge) . I have used n310 before without any problems. Switched to Clays because it is alot cheaper than V V powders.

[revchuck]

Is it possible to have a load that has too much pressure, but still just make power factor?

Yup. I don't have access to the loading data, but if I wanted to produce an overpressure load, N310 and a 230 grain jacketed bullet would one of the recipes. Having said that, you may be within specs; I just don't know.

You can safely make Major with 230 grain jacketed bullets by using a slightly slower powder, like N320, WW231, or Bullseye. I'm old school - I use Unique (the new version).

[harley45]

I to have found federal primers to be softer and flatten easier thatn cci or Winchester primers I have used about 2k of 4.2 behind a 230jrn with no problems in my 1911 with good results but I use Winchester primers.

[John Dunn]

I'm old school - I use Unique (the new version).

I can't stop laughing!

[CSEMARTIN]

harley45,

do you have any chrono data using 4.2 grains of N310?

chris

[mda]

Manual says that 4.2 grain is the max load. I would go with a slower burning powder with the 230 grain bullet.

230 FMJ-RN Hornady

Start Max

gn FPS gn FPS

N310 3,7 719 4,2 771

N320 4,9 784 5,2 850

N340 5,9 830 6,4 912

N350 6,7 845 7,2 920

[CSEMARTIN]

mda,

With 4.3 grains of N310, I'm getting 730 fps. How are you getting 771 fps with 4.2 grains? Did I read your post correctly?

[harley45]

CSEMARTIN out of my 5 inch Kimber and my 5inch Les Baer with a zero 230 rn fmj seated at 1.250 4.2 gr 310 I get between 750-760 crimp is .470

Eric

[38superman]

Just because a load barely makes major PF doesn't mean it cant be too hot in terms of pressure.

I never like fast powder / heavy bullet combinations. It is asking for trouble.

I would recommend going to a slower powder with a heavy bullet in the 45 ACP.

I like vv340 or AA No5 but if you don't want to go that slow try vv320.

If you insist on using 310 try a different primer such as Winchester Large Pistol or CCI 300.

Back off your load a bit and work back up to 4.3 gr.

If the different primers flatten, you may be treading on thin ice with pressure.

Are you tampering with the flash holes on the brass?

Remember, there are dozens of factors that can affect pressure.

Temperature.

Chamber tolerance

Lot to lot variations in primers

Manufacturing tolerances in bullets and brass.

The list goes on and on.

Err on the side of caution.

Tls

[mda]

CSEMARTIN,

The charge/velocity listed is from the VihtaVuori manual. All guns are different and will result in different velocity for same charge. I personal would not use 310 with a 230 grain bullet. I feel that the powder is to fast. e.g. high pressure spikes. You can see that in the listing of the other slower powders, more powder with higher velocitys and still below SAMII safe pressures. With the faster powder you will have an initial high pressure spike with most of the powder burning before the bullet is even half way down the barrel.

[CSEMARTIN]

tlshores and mda,

Thanks for the response. I am starting to wish I hadn't bought 8#'s of 310!! I love the load though.

[Harmon]

is it a revo?

if not shoot a winchester primer, or a federal mag pistol primer...the mag federal primers has a thicker cup, plus a hotter mix that allows the use of less powder to make the PF.

i once had a federal primered 45 self-decap with a load of titegroup and 185 montana gold JHP...the case was a touch too short and it was remington brand( big radius on primer pocket) when the round fired, im guessing the primer set back enough to come out of that remington case..

i think that case was .010 inch too short...maybe..

if you have another 45, chrono that load in it and see where your at...also look at the primers...your gun might be showing signs of excess headspace, not pressure.